1. Field of the Invention
The present invention relates to a multi-input switch which is suitable for use in radios, CD recorders, and navigation systems for automobiles, for example.
2. Description of the Related Art
There is a conventional multi-input switch disclosed in U.S. Patent Publication No. 5,613,600.
As shown in FIGS. 8 to 11, in the multi-input switch, a rotatively-operated component "R" is operated by the rotation of an operation knob "S" while a push-switch "P" is operated by the movement of the operation knob "S" in a direction perpendicular to the axis of the operation knob "S".
The rotatively-operated component "R" is formed such that a rotary member 53 thereof is rotatably attached through a shaft 54 to a box-shaped casing 51 to which a contact member 50 having a pair of resilient contact arms 50a and 50b is fixed. A contact plate 52 sliding in contact with the resilient contact arm 50a in the box-shaped casing 51 is fixed to the rotary member 53.
The push-switch "P" is formed such that a contact portion (not shown) is arranged within a cage 55 to which an operation button 56 is movably attached.
As shown in FIG. 11, a flat-plate-shaped insulating base plate 58 comprises a recess portion 58a for guiding the rotatively-operated component "R", a pair of guide rails 58b for preventing the rotatively-operated component "R" from coming off disposed on both sides of the recess portion 58a, and a recess portion 58c and a protruded portion 58d, each spaced from the recess portion 58a.
Furthermore, in the insulating base plate 58, fixed terminals 59 are embedded in an exposed state in the recess portion 58a.
The rotatively-operated component "R" is attached to the insulating base plate 58; the casing 51 of the rotatively-operated component "R" is placed on the recess portion 58a of the insulating base plate 58, the guide rails 58b are urged in contact with step portions 51a of the casing 51, and the casing 51 is elastically pressed by a torsion coil spring 60 supported by the protruded portion 58d.
When the rotatively-operated component "R" is attached, the resilient contact arm 50b is in contact with contacts 59a exposed on the insulating base plate 58.
The push-switch "P" is attached to the insulating base plate 58; the cage 55 of the push-switch "P" is fitted into the recess portion 58c on the insulating base plate 58, and the operating button 56 opposes a protruded portion 51b of the casing 51 of the rotatively-operated component "R".
Furthermore, the operation knob "S" is attached to the rotary member 53 of the rotatively-operated component "R" by a screw 61.
The operation of the conventional multi-input switch will now be described; when the operation knob "S" is rotated, the rotary member 53 rotates about the shaft 54 in accordance with the rotation, the contact plate 52 attached to the rotary member 53 also rotates to be contacted with and separated from the resilient contact arm 50a for switching the contact, the switching is derived via the resilient contact arm 50b and the contact 59a to the fixed terminal 59.
Next, when the operation knob "S" is pushed in the direction perpendicular to the axis of the shaft 54, i.e., the direction indicated by the arrow "Y", the operation knob "S" moves in the direction of the arrow "Y" against the torsion coil spring 60 accompanying the rotatively-operated component "R".
At this time, in the state that the electrical connection of the rotatively-operated component "R" is maintained, i.e., the resilient contact arm 50b is sliding on the contact 59a of the fixed terminal 59, the protruded portion 51b of the casing 51 pushes the operation button 56 of the push-switch "P".
Thus, the contact of the push-switch "P" is switched, and then when the pressing is relieved, the rotatively-operated component "R" returns to the original position accompanying the operation knob "S" owing to the torsion coil spring 60.
At this time, in the state that the electrical connection of the rotatively-operated component "R" is maintained, i.e., the resilient contact arm 50b is sliding on the contact 59a of the fixed terminal 59, the operation button 56 returns to the original state, so that the contact of the push-switch "P" is switched.
In this manner, the rotatively-operated component "R" is operated by the rotation of the operation knob "S" while the push-switch "P" is operated by the movement of the operation knob "S" in the direction perpendicular to the axis.
The conventional multi-input switch involves a problem that the size thereof is large because the rotatively-operated component "R" moves when the operation knob "S" is moved in the direction perpendicular to the axis.
Also, in order to maintain the electrical connection of the rotatively-operated component "R" when the rotatively-operated component "R" is moved, it is required that the resilient contact arm 50b slide on the contact 59a of the fixed terminal 59, so that the elongation of the component life is difficult and the manufacturing cost is increased due to the complicated structure.
Furthermore, since two components, i.e., the rotatively-operated component "R" and the push-switch "P", are operated by the operation knob "S", there is another problem that numerous switches cannot be switched.